Symbiotic network on layers

ABSTRACT

The technology relates to a system on chip (SoC). The SoC may include a plurality of network layers which may assist electrical communications either horizontally or vertically among components from different device layers. In one embodiment, a system on chip (SoC) includes a plurality of network layers, each network layer including one or more routers, and more than one device layers, each of the plurality of network layers respectively bonded to one of the device layers. In another embodiment, a method for forming a system on chip (SoC) includes forming a plurality of network layers in an interconnect, wherein each network layer is bonded to an active surface of a respective device layer in a plurality of device layer.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the filing date of U.S.Provisional Patent Application No. 62/857,578 filed Jun. 5, 2019, thedisclosure of which is hereby incorporated herein by reference.

BACKGROUND

A system on chip (SoC) is an integrated circuit that generally includescomponents of a computer or other such electrical system on a singlesubstrate in a single housing. The components within a SoC may includeany combination of processors, memory, controllers, power management,network controllers, and other such computer components. By integratingthese components onto a single substrate in a single housing of a SoC,the amount of space taken up by the components may be reduced relativeto if the components were implemented discretely.

Communication between the components of the SoC, as well ascommunication between components of the SoC and off-package components,such as memory not located in the SoC housing, is controlled through theuse of communication subsystems. Communication subsystems may route databetween the components of the SoC via one or more computer buses and/orcrossbars. As the number of components within a SoC increases, thenumber of buses and crossbars increases. In some instances, the lengthof the buses and crossbars may also increase. The increase in the numberof buses and crossbars, as well as the length of the buses and crossbarsmay lead to communication delays and increased power usage by the SoC.

In SoCs having a three-dimensional (3D) packaging structure, such as aSoC having multiple layers, with components of a computer or other suchelectrical system on substrates in each layer, the 3D footprint of thecomponents may further limit the possible communication paths betweenand on the layers. In this regard, the number of possible pathsavailable to communications subsystems between layers may be limited tolocations where components are not overlapping on adjacent stackedlayers. Accordingly, the length of the communication paths betweencomponents located on different layers may be increased, which may leadto communication delays and increased power usage by the SoC. Moreover,a larger component positioned on one layer may block a portion of asubstrate of another layer, thereby requiring the communicationsubsystem of the second layer to route around the component.

Some SoCs have implemented network-on-chip (NoC) communicationsubsystems. In a NoC communication subsystem, networking interfaces,each associated with a component of the SoC, packetize data to be passedto other components. The networking interfaces communicate with a set ofinterconnected routers which direct the packetized data to its intendeddestination component. A networking interface at the destinationcomponent may de-packetize the data and pass the de-packetized data intothe destination component.

A NoC communication subsystem may decrease communication delaystypically encountered in bus and crossbar communication subsystems bydirecting the packetized data through a more direct communication pathto its destination component. However, NoC communication subsystems maystill suffer from delays caused by inefficient communication pathsresulting from the limited amount of real estate on the substrate causedby the density of components on the substrate in the SoC. In thisregard, the NoC communication subsystem may need to be routed aroundcomponents, thereby increasing the length of the communication paths.

Processors generally use NoC communication subsystems to retrieve datefrom cache memory located off of the processor die, such as L2 or L3cache memory. Given the limited space around a processor die, the sizeof L2 cache memory may be limited. As such, the processor may need torely on typically slower L3 cache memory that is located further fromthe processor die or off-package cache memory, such L4 cache memorywhich is typically located outside of a SoC. The use of a NoCcommunication subsystem may provide more efficient read and writeoperations to L3 and L4 cache than previously possible with buses andcrossbar communication subsystems. However, due to the distance dataneeds to travel to and from the processor to L3 and L4 cache memory, theprocessor may be required to delay processing as it waits for data fromthe L3 and L4 cache memory.

SUMMARY

Aspects of the disclosure provide a system on chip (SoC). The SoC mayinclude a plurality of network layers and a device layer. The pluralityof network layers may include a first network layer and a second networklayer. Each network layer may include one or more routers. The firstdevice layer may include one or more components. The first device layermay have an active surface and a second opposite surface. The activesurface may be bonded to the second network layer and the secondopposite surface may be bonded to the first network layer.

In some examples, the first network layer and the second network layerare configured to route data to and from the one or more components onthe first device layer. In some instances, at least one of the one ormore components includes a network interface, wherein the networkinterface connects the at least one component to the first network layerand the second network layer via conductive structures. In someinstances, the conductive structures comprise one or more of traces,vias, contacts, or terminals. In some instances, the network interfaceis configured to packetize and depacketize the data.

In some examples, the first device layer comprises at least one of anapplication specific integrated circuit (ASIC) layer or a memory layer.

In some examples, the plurality of network layers each comprise anactive surface having one or more contacts; and a second surfaceopposite the active surface having one or more contacts. In someinstances, the second surface of the second network layer is bonded tothe active surface of the first device layer and the active surface ofthe first network layer is bonded to the second surface of the firstdevice layer.

In some examples, the SoC includes a memory layer including an activesurface having one or more contacts, the active surface of memory layerbeing bonded to the active surface of the second network layer. In someinstances, the memory layer includes one or more memory segments, eachof the one or more memory segments being connected to at least one ofthe one or more routers in the second network layer via one or moreconductive structures. In some instances, the second network layer isconfigured to route data between the one or more components in the firstdevice layer and the one or more memory segments. In some examples, thebonds between the first device layer and first and second networklayers, and the bonds between the memory layer and the second networklayer are formed via ZiBond direct bonding and/or direct bondinterconnect (DBI) hybrid bonding.

In some instances, the SoC includes a second device layer including oneor more components, the second device layer having an active surface anda second opposite surface, the second opposite surface being bonded tothe active surface of the second network layer.

In some instances, the SoC includes a third device layer including oneor more components, the third device layer having an active surface anda second opposite surface, the active surface being bonded to the secondsurface of the first network layer. In some examples, the first andsecond network layers are configured to route data between the one ormore components on the third device layer and the one or more componentsin the second device layer.

In some instances, the bonds between the first device layer and firstand second network layers, the bonds between the second device layer andthe second network layer, and the bonds between the third device layerand the first network layer are formed via ZiBond direct bonding and/ordirect bond interconnect (DBI) hybrid bonding.

In some examples, the one or more components include one or more ofprocessors, graphics processing units (GPUs), logic boards, digitalsound processors (DSP), or network adaptors. In some instances, thefirst and second network layers are configured to ignore faulty memorysegments or faulty processors.

In some examples, the one or more routers of the first and secondnetwork layer are connected via one or more routing traces in eachrespective network layer.

In some instances, the first and second network layers are connected tomemory located outside of the SoC.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side, cross-section view of a SoC including three layers inaccordance with aspects of the disclosure.

FIG. 2 is a top-down view of an application specific integrated circuit(ASIC) layer in accordance with aspects of the disclosure.

FIG. 3 is a side, cross-section view of an ASIC layer in accordance withaspects of the disclosure.

FIG. 4 is a top-down view of a network layer in accordance with aspectsof the disclosure.

FIG. 5 is a cross-section, side view of the interconnections of multipledevice layers in accordance with aspects of the disclosure.

FIG. 6 is a top-down view of a memory layer in accordance with aspectsof the disclosure.

FIG. 7 is a cross-section, side view of data communication paths throughmultiple device layers and multiple network layers in accordance withaspects of the disclosure.

FIGS. 8A and 8B depict cross-section, side views of the interconnectionsof device layers and network layers with fillers disposed therein inaccordance with aspects of the disclosure.

FIG. 9A is a top-down view of components of a network layer and a devicelayer in accordance with aspects of the disclosure.

FIG. 9B is a top-down view of data communication path through multiplenetwork layers among different device layers in accordance with aspectsof the disclosure.

FIG. 10A shows the interconnection of device layers and network layersin accordance with aspects of the disclosure.

FIG. 10B shows the interconnection of device layers and network layersin accordance with aspects of the disclosure.

FIG. 11 is a perspective view of device layers and a memory layer with adefective memory segment in accordance with aspects of the disclosure.

DETAILED DESCRIPTION

The technology relates to a system on chip (SoC) having one or morenetwork layers. Conventional SoCs utilize communication subsystems, suchas NoCs to enable communication between components in the SoC. However,due to the limited availability of space on the substrate of the SoC,the ability to efficiently route the communication subsystems may beimpeded, potentially leading to reduced speed of data communicationbetween components and, in some instances, resulting in processingbottlenecks. As described herein, the communication subsystem may bemoved to one or more network layers, located above, below, or adjacentto device layers, such as application specific integrated circuit (ASIC)layers and memory layers. By doing such, more efficient routing of thecommunication subsystem may achieved as the routing of the communicationsubsystem may not be obstructed or otherwise limited by components onthe device layers. As a result, the distance data travels duringcommunication may be reduced and the routing of the data to itsdestination may be more direct.

In some instances, a memory layer may be positioned above, below, oradjacent a network layer to provide increased memory availability toprocessors or other components on the ASIC layer. The memory on thememory layer may operate as L2 cache memory. As a result of the largeramount of L2 cache memory on the SoC, the number of requests for datafrom memory that is located further from the processor die, such as L3cache memory or off-package memory, such as L4 cache memory, may besignificantly reduced, thereby limiting or removing the need foroff-package data requests and allowing for increased frequency ofoperation.

FIG. 1 illustrates, a system on chip 101 comprised of two device layersand a network layer. The SoC 101 includes a first device layer, such asan application specific integrated circuit (ASIC) layer 102, a networklayer 104, and a second device layer, such as a memory layer 106. Theexemplary structure shown in the system on chip 101 only depicts onenetwork layer 104 formed between the ASIC layer 102 and the memory layer104 for ease of explanation of the operation of the network layer 104.It is noted that additional network layers may be formed among manydevices layer in the system on chip 101 as needed, which is described ingreater detail herein.

The network layer 104 may have an active surface 122 and a secondsurface 115 opposite the active surface 122. The active surface 122 ofthe network layer 104 may be bonded to an active surface 116 of thememory layer 106. The second surface 115 of the network layer 104 may bebonded to an active surface 112 of the ASIC layer 102. Although notshown, a second surface 113 of the ASIC layer 102 may include or connectwith other electrical components, is described in detail herein.

As used in this disclosure with reference to the ASIC layer 102, thenetwork layer 104, the memory layer 106, or another layer having aplanar surface, a statement that an electrically conductive structure,such as contacts, terminals, etc. is “at” or “on” a surface of a layerindicates that, when the respective layer is not assembled with anyother element, the electrically conductive structure is available forcontact with a theoretical point moving in a direction perpendicular tothe surface of the layer toward the surface of the layer from outsidethe layer. Thus, a terminal or other conductive structure which is at asurface of a layer may project from such surface; may be flush with suchsurface; or may be recessed relative to such surface in a hole ordepression in the respective layer. In some embodiments, the conductivestructure may be attached to the surface or may be disposed in one ormore layers of coating on the said surface.

In FIG. 1, the first direction D1 is referred to herein as “horizontal”or “lateral” direction, which may be considered an x-axis), whereas thedirections perpendicular to the SoC 101, illustrated by second directionD2 is referred to herein as upward or downward direction and are alsoreferred to herein as the “vertical” direction or a z-axis. FIG. 2illustrates a third direction D3 that is perpendicular to direction D1.Direction D3 may also be considered a “horizontal” or “lateral”direction or a y-axis. The directions referred to herein are in theframe of reference of the structures referred to. Thus, these directionsmay lie at any orientation to the normal or gravitational frame ofreference. A statement that one feature is disposed at a greater height“above a surface” than another feature means that the one feature is ata greater distance in the same orthogonal direction away from thesurface than the other feature. Conversely, a statement that one featureis disposed at a lesser height “above a surface” than another featuremeans that the one feature is at a smaller distance in the sameorthogonal direction away from the surface than the other feature.

FIG. 2 shows a top down view of the ASIC layer 102 with the activesurface 112 removed for clarity. The ASIC layer 102 includes a substrate202 and components mounted, fabricated or otherwise positioned on thesubstrate 202. The components include processors 220A-220C, graphicsprocessing unit (GPU) 230, logic board 260, digital sound processor(DSP) 270, and network adaptor 280. The ASIC layer 102 may include anycombination of components typically found in an ASIC device or othersuch computing devices. The components shown mounted on the substrate202 are for illustration purposes only. More than one ASIC layer orother types of the device layers may be included on a SoC.

The term “component,” as used herein, may refer to one or morefunctional blocks. Functional blocks may be singular or complex circuitsbuilt in or on a layer to perform certain electrical functions. Thecomponents may be interconnected internally or externally together toform numerous microcircuits, larger circuits, or any suitable types ofintegrated circuits. The components and functional blocks as describedherein are applicable to any types or numbers of electrical structuresand/or elements as needed.

Each component in the ASIC layer 102 may include a network interfacethat enables the component to communicate over the network in thenetwork layer 104, described herein. FIG. 2 shows network interfacesincluding network interfaces 221A-221C in processors 220A-220, networkinterface 231 in GPU 230, network interface 261 in logic board 260,network interface 271 in DSP 270, and network interface 281 in networkadaptor 280. Although the network interfaces in FIG. 2 are illustratedas being within respective components, the network interfaces may belocated adjacent to their respective components.

The substrate 202 of the ASIC layer 102 may be constructed from one ormore semiconductor materials, such as materials including at least oneof crystalline silicon (e.g., Si<100> or Si<111>), silicon oxide,strained silicon, silicon germanium, germanium, doped or undopedpolysilicon, doped or undoped silicon wafers and patterned ornon-patterned wafers silicon on insulator (SOI) (e.g., buried dielectriclayer disposed on a silicon crystalline substrate), carbon doped siliconoxides, silicon nitride, doped silicon, germanium, gallium arsenide,glass and sapphire. In some embodiments, the substrate 202 (or any ofthe substrates disclosed herein) may be made from a material such assemiconductor material, ceramic, glass, liquid crystal polymer material,a composite material such as glass-epoxy or a fiber-reinforcedcomposite, a laminate structure, or a combination thereof.

The vertical distance between device layers and/or between device layerand network layers can be as small as microns when the layers are bondedface-to-face (e.g., active surface to active surface, active surface tosecond surface, or second surface to second surface, as describedherein). The vertical distance from the base of a layer through thelayer to an adjacent face-to-face bonded layer, such that the distanceincludes the thickness of the layer, may be 5 μm-55 μm, although thedistances may be less or more depending on the thickness of thesubstrates and layers. The lateral distance across a layer may beseveral millimeters. In this situation, additional circuitry such asrepeaters, inverters and/or buffers may be needed to maintain the signalintegrity needed to travel across that electrical load over that longerdistance. For example, if a there is a multi-processor device, thedistance needed between a given processor to a shared memory or acrossbar may be a few millimeters due to the need to traverse the widthof another processor.

Referring to FIG. 1, the active surface 112 and the second surface 113of the ASIC layer 102 may be configured to provide electricalinterconnections between the ASIC layer 102 and other layers in the SoC101 or other components external to the SoC 101. For instance, and asshown in the enlarged, side view of the ASIC layer 102 in FIG. 3, thesecond surface 113 may include conductive structures including terminals303 on its lower surface 301. The terminals 303 may be configured toform electrical connections between components in the ASIC layer 102,network layer 104, and/or memory layer 106, with one or more componentsexternal to the SoC 101, such as a printed circuit board (PCB), powersupply, etc. For clarity, components such as processors 220A-220C, GPU230, etc., are not shown in the ASIC layer 102 of FIG. 3. One exemplaryembodiment of where the components may be located in the ASIC layer 102is illustrated in FIG. 5, which will be further described herein. Theterminals 303 may be arranged according to a surface-mount packagingtype, such as a ball grid array (BGA), pin grid array (PGA), or landgrid array (LGA). In some instances, there may be around 1,000 terminalsat the lower surface 301 of the second surface 113.

As further illustrated in FIG. 3, the active surface 112 of the ASIClayer 102 may include conductive structures including contacts 313 onits upper surface 311. The contacts 313 may be configured to align withcorresponding contacts 314 on the network layer 104 (as shown in FIG. 5)to form electrical connections between the network layer 104 and theASIC layer 102.

Although not illustrated, the ASIC layer 102, including active surface112 and second surface 113, may include conductive structures configuredto connect components in the ASIC layer 102 (e.g., processors 220A-220C,GPU 230, etc.,) through their respective network interfaces (e.g.,221A-221C, 231, etc.,) with the network layer 104, other components inthe ASIC layer 102, and/or the terminals 303. Such conductive structuresmay include traces extending in the horizontal direct D1 along the lowerand upper surfaces 301, 311 of the second surface and active surface112, respectively. The traces may also extend in the directionperpendicular to D1 along the lower and upper surfaces 301, 311,illustrated as direction D3 in FIG. 2. In some instances, the traces maybe contained within the ASIC layer 102. In some examples, components inthe ASIC layer 102 may directly connect with terminals 303 and/or withother components without the use of network interfaces.

The conductive structures may also include conductive interconnects suchas vias 162 (e.g., through silicon vias (TSVs), through oxide vias(TOVs) or through-glass vias (TGVs)) extending in the vertical directionD2 between the active surface 112 and the second surface 113, as furthershown in FIG. 3. In some instances, the conductive interconnects mayextend in the horizontal directions D1 and/or vertical direction D2within or on the substrate 202. The conductive interconnects and vias162 may terminate at a contact or terminal, such as terminals 303 andcontacts 313. Although FIG. 3 illustrates the vias 162, as stopping atthe bases of the active surface 112 and second surface 113, that is, thevias do not extend to the upper surface 311 or lower surface 301, thevias 162 may extend through and/or beyond the active surface 112 and/orsecond surface 113 to facilitate connection to the upper network layer104 or to the underlying interconnection structures.

FIG. 4 shows a top down view of the network layer 104 with the activesurface 122 removed for clarity. The network layer 104 includesnetworking components mounted or otherwise positioned on the networklayer 104. The networking components may include routers illustrated ascircles, such as routers 410-416, and routing traces illustrated aslines, such as routing trace 420. As discussed herein, the routers410-416 and routing traces 420 may connect, through electricalinterconnections formed by contacts, terminals, and other conductivestructures, with memory in the memory layer 106. The routers may alsoconnect with the components in the ASIC layer 102 through the networkinginterfaces 221A-221C, 231, 261, 271, 281. Although sixteen routers areshown in FIG. 4, any number of routers may be present in the networklayer 104. Other components, which may include active or passivecomponents, including capacitance layers, clock structures (e.g., treeor part of tree clock structures) memory, and/or analog circuits mayalso be included in the network layer 104 as needed.

The network layer 104 may be constructed from one or more semiconductormaterials, conductive materials or other materials described herein withregard to the substrate 202. In some instances, more than one networklayer 104 may be included on a SoC. By providing additional networklayers 104, larger blockages, such as from taller stacks formed fromstacking multiple layers, such as device layers and memory layers, maybe routed around, which is described herein.

As mentioned herein, the ability to efficiently route a communicationsubsystem on a device layer, such as an ASIC layer, may be impeded bylimitations in space and blockages created by large components, such asa chip die, on the ASIC layer. Such limitations and blockages maypotentially lead to inefficient network routings which may in turnreduce the speed of data communication between components and, in someinstances, result in processing bottlenecks. In some instances whereinmultiple device layers are vertically stacked in a three dimensional(3D) packaging structures, large components in a device layer mayconstrain the routing options between different components in nearbydevice layers, such as by projecting into other device layers and/ornetwork layers.

By utilizing additional network layers located above, below, and/oradjacent to the device layers, routing options may be efficientlyincreased and boosted. The additional network layers may serve as signalrelay pathways/bus/checkpoints to re-direct or switch the signal from afirst component to a destination second component, either horizontallyor vertically, by efficient computational algorithms from the networklayers. Each network layer may perform the computational algorithmindependently or collectively to determine a most efficient datacommunication path and/or operations among different components. Thus,more efficient routing of the communication subsystem may be achieved asthe routing of the communication subsystem may not be obstructed orotherwise limited by locations or sizes of components on the devicelayers. As a result, the distance data travels during communication maybe reduced and the routing of the data to its destination may be moredirect.

FIG. 5 depicts a cut-away side view of a portion of an interconnectionstructure of a multi-layered SoC 501 having a three-dimensional (3D)packaging structure. The SoC 501 includes a first device layer 502 a, asecond device layer 502 b, a first network layer 504 a, a second networklayer 504 b, and a memory layer 506. The second device layer 502 b ispositioned between the first network layer 504 a and the second networklayer 504 b. The first device layer 502 a and the second device layer502 b may be ASIC layers similar to the ASIC layer 102 described herein.For instance, the first device layer 502 a and second device layer 502 bmay include vias 565 a and 565 b, respectively. In some examples, thefirst device layer and/or second device layer 502 b can be any otherdevice layer, such as a memory layer, or a network layer. Although onlytwo network layers 504 a, 504 b, and three device layers 502 a, 502 b,and 506, are shown in FIG. 5, it is noted that there may be any numberof network layers and device layers. For instance, the SoC may includethree network layers, three ASIC layers, and a memory layer. In anotherexample, the SoC may include a single ASIC layer and many network andmemory layers. In any configuration, the network layers may beconfigured to connect the device layers together.

The network layers 504 a and 504 b may be configured to provideelectrical interconnection between the network layers and theirrespective interfacing layers (e.g., device layers 502 a and 502 b, aswell as memory layer 506 in the SoC 501.) For example, active surfaces542 a and 542 b of the network layers 504 a and 504 b may includecontacts 515 a and 515 b, respectively. The second surfaces 541 a and541 b of the network layers 504 a and 504 b may include contacts 544 aand 544 b, respectively. These contacts, (e.g., contacts 515 a, 515 b,544 a, and 544 b) may align with contacts on adjacent device layers. Forexample, contacts 544 a on the second surface 541 a of network layer 504a may connect with contacts 513 a on the active surface 511 a of ASIClayer 502 a. Contacts 544 b on the second surface 541 b of network layer504 b may connect with contacts 513 b on the active surface 511 b ofASIC layer 502 b. Contacts 515 a on the active surface 542 a of networklayer 504 a may connect with contacts 517 b on the second surface 545 bof ASIC layer 502 b. Contacts 517 a on the second surface 545 a of ASIClayer 502 a may connect with other electrical components. In someinstances, there may be hundreds of thousands of electrical connectionsformed between contacts on the network layers 504 a, 504 b and thedevice layers 502 a, 502 b, and 506.

The network layers 504 a, 504 b may include networking components suchas described in with regard to network layer 104. In this regard,network layers 504 a, 504 b may include routers and other conductivestructures configured to connect components within the device layers orotherwise route data between different device layers and network layers.The conductive structures may be the same as those described herein withregard to the ASIC layer 102, such as traces, interconnects, and vias,including vias 564 a and 564 b shown in FIG. 5. In operation, thenetwork layers 504 a, 504 b may take packetized data from a component onone device layer and route the data to one or more recipient componentson the same or different device layers, where the data is depacketizedand delivered to the recipient components.

The memory layer 506 may be similar to memory layer 106 describedherein. As shown in FIG. 5, memory layer 506 is disposed on the secondnetwork layer 504 b. Contacts 555 on the active surface 556 of thememory layer 506 may be arranged such that they align, and in someinstances connect with, contacts 515 b on the active surface 542 b ofthe network layer. There may be millions of electrical connectionsformed by the contacts on the network layer 504 b and the memory layer506.

The memory layers, such as memory layers 106 and 506, may include one ormore memory segments. For instance, and as shown in FIG. 6, memory layer506 includes 25 memory segments, including memory segments 601-605,although any number of memory segments may be possible. The memorysegments may be NAND memory or other such volatile and non-volatilememory including MRAM, NRAM, FE-RAM, etc.

Production of the memory segments may include creating a memory waferand cutting the memory wafer into memory segments of a chosen size. Inthis regard, each memory wafer may have the same design to allow forreusability of the memory segments by different SoC designs. Forinstance, the memory wafer may be created in set increments, such as 1×1mm, 2×2 mm, 4×4 mm, etc. The memory wafer may then be cut or otherwiseseparated into memory segments sized for the SoC they are being used.For example, the die size of SoC 101, that is the size of the ASIC layer102, may be 10×10 mm. To form memory layer 106, four memory wafershaving a size of 5×5 mm may be cut into 1×1 mm segments, resulting in100 1×1 mm memory segments being formed. The 100 memory segments maythen be arranged in the memory layer 106 such that the memory layer 106has the same size as the die (10×10 mm). Although the memory segmentsare described as being 1×1 mm in the foregoing example, the memorysegments may be any size. For instance, a 20×20 mm die may have acorresponding memory layer made up of a 10×10 array of 2×2 mm memorysegments or a 10×20 mm die may have a corresponding memory layerincluding a 5×10 array of 2×2 mm memory segments. In some instances,multiple memory segments may be formed on the same wafer. For instance,a 10×10 mm memory array may be made up of a 10×10 mm memory wafer havingtwo 5×10 mm memory segments. In other words, memory segments may beformed directly on a wafer, as opposed to by cutting the wafer.

The size of the memory layers, such as memory layers 106 and 506, may bethe same or different than the other device layers, such as ASIC layersand network layers. In some instances, the dimensions of the memorylayer, such as its width and length may match a multiple of the memorydimensions so that the interconnection of the memory layer coincideswith the other device layers. In another embodiment, a die-to-waferassembly may be used. In this embodiment the memory layer may not bematched to the device layers, such as the ASIC layer or network layer,but the network layer may match the memory layer or ASIC layer.

The layers of the SoCs described herein, such as SoC 101 and 501 may bebonded in a stacked arrangement using various bonding techniques,including using direct dielectric bonding, non-adhesive techniques, suchas a ZiBond® direct bonding technique, or a DBI® hybrid bondingtechnique, both available from Invensas Bonding Technologies, Inc.(formerly Ziptronix, Inc.), a subsidiary of Xperi Corp. (see forexample, U.S. Pat. Nos. 6,864,585 and 7,485,968, which are incorporatedherein in their entirety). Referring to FIG. 5, these bonding techniquesmay enable the contacts on of the device layers to bond to contacts inthe network layers. For instance, contacts 513 a on the active surface511 a of the first device/ASIC layer 502 a may be bonded to the contacts544 a in the second surface 541 a of the first network layer 504 a.Similarly, this process may enable the contacts 515 a on the activesurface 542 a of the first network layer 504 a to bond to the contacts517 b on the active surface 545 b of the second device layer 502 b. Thecontacts 555 on the active surface 556 of the memory layer 506 may bondto the contacts 515 b on the active surface 542 b of the network layerusing the same bonding techniques. The contacts may have an extremelyfine pitch. For example, the contacts may be at a pitch as low asapproximately 1μ-10μ, or in some instances, as low as around 100 mm orgreater that 10μ.

In the embodiment depicted in FIG. 5, the device layers 502 a, 502 b,and 506 are each connected to at least one of network layers 504 a and504 b to produce data communication paths between the layers. Forinstance, ASIC layer 502 a is connected to the memory layer 506 via thevarious connections between network layers 504 a and 504 b, as well asASIC device 502 b.

As described, components may be formed on the device layers. Forinstance, ASIC layer 502 a includes components 512, 514, and 516 andASIC layer 502 b includes components 522, 524, and 526, as shown in FIG.5. It is noted that the components shown in FIG. 5 may be the same orsimilar to the components 220A-220C, 230, 260, 270, 280 depicted in FIG.2. The components of memory layer 506, including components 532, 534,and 536 may include components such as NAND memory or other suchvolatile and non-volatile memory including MRAM, NRAM, FE-RAM, etc.Alternatively, the components 512, 514, 516, 522, 524, 526, 532, 534,and 536 may be any suitable electrical components designated to performcertain functions as needed. Although only three components are shown ineach active surface of ASIC layers 502 a and 502 b, as well as in activesurface 556 of memory layer 506, it is noted that each device layer mayhave any number of components and that the components may be placed atany position and/or on any surface.

FIG. 7 depicts another embodiment of a stacked SoC 700 including sixdevice layers 702 a, 702 b, 702 c, 702 d, 702 e, and 706 and fournetwork layers 704 a, 704 b, 704 c, and 704 d. The device layer 706 maybe similar to the memory layers 106 and 506, and device layers 702 a-emay be similar to ASIC layers 102, 502 a, and 502 b. The network layers704 a-d may be compared with network layers 104, 504 a, and 504 b, andmay facilitate communication of data between the device layers. Each ofthe network layers is positioned between a respective pair of devicelayers. For example, and as further shown in FIG. 7, network layer 704 ais positioned between device layers 702 a and 702 b, network layer 704 bis positioned between device layers 702 b and 702 c, network layer 704 cis positioned between device layers 702 d and 702 e, and network layer704 d is positioned between device layers 702 e and 706. It is notedthat the conductive structures, such as contacts, terminals, vias, etc.,are not shown for clarity. Similarly, or active and secondary surfacesformed in the network layers and the device layers are not shown in FIG.7 for clarity and ease of description.

In some instances, device layers may be bonded face to face without anetwork layer positioned there between. In this regard and as furthershown in FIG. 7 a direct bonding process (e.g., a face-to-face) isutilized between the device layers 702 c and 702 d at bonding interface728, thereby eliminating the need for a network layer between the devicelayers. In this regard, communication between device layers 702 c and702 d may be made between connections at bonding interface 728.

Device layers 702 a-702 e and 706 may include components. For example,device layer 702 a includes components 732 and 734, device layer 702 bincludes components 736 and 738, device layer 702 c includes components740, 742, and 744, device layer 702 d includes components 746, 748, and750, and device layer 702 e includes component 730. For clarity, not allcomponents are illustrated. The components shown in FIG. 7 may be thesame or similar to the components 220A-220C, 230, 260, 270, 280 depictedin FIG. 2 and components 532, 534, and 536 depicted in FIG. 5.

As further shown in FIG. 7, the positioning of components within thedevice layers may constrain communication routing options betweencomponents and/or different layers. For example, a direct communicationpath, such as shown by dotted line 754, between component 732 in devicelayer 702 a and component 730 in device layer 702 e may be blocked bycomponent 736 in device layer 702 b.

By utilizing multiple network layers, efficient communication routes maybe used to circumvent the blockages created by the components. In thisregard, the network layers may serve as electrical communicationpathways capable of determining and providing efficient communicationpathways among components that may be positioned vertically and/orhorizontally apart. Each network layer may be programmed with acomputational algorithm or other such logic for determining the mostefficient communication paths among the components vertically orhorizontally located at the different device layers. Each network layers704 a-704 d may perform the computational algorithm or logicindependently to determine a most efficient data communication pathwayand/or operation among between different components. For example, whenan electrical communication is requested between component 732 in devicelayer and component 730 in device layer 702 e, an efficientcommunication route, illustrated by solid line 752, may be determined bythe network layers 704 a, 704 b, and 704 c. In this regard, networklayer 704 a may determine the most efficient path to route the data fromcomponent 732 in device layer 702 a to network layer 704 b is betweencomponents 736 and 738. Network layer 704 b may then determine the mostefficient path to network layer 704 c is between components 742 and 744in device layer 702 c and components 748 and 750 in device layer 702 d,as opposed to travelling around components 744 and 750, as shown bydashed lines 753. Network layer 704 c may then pass the data tocomponent 730 in device layer 702 e. In some examples, the networklayers may perform the computational algorithm or logic collectively asneeded.

In one example, the network layers may include at least one look-uptable (LUT) or other such storage area, capable of providing a look-upmechanism. The look-up mechanism may utilize information from thelook-up table to store, retrieve and direct data among the multiplenetwork layers or device layers nearby. The look up table may be acircuit which can be programmed to produce an output signal in responseto an input signal so as to perform a logical function. It is noted thatthe functions, logic or the programs in the network layers may be designdependent so that each network layer may meet different electricalperformance and requirements as needed.

Furthermore, the network layers may also be programmed to provideinformation regarding the layout, such as the physical locations, of thecomponents formed in each device layer, network layer, and/or memorylayer. Such information may assist the network layers to make routingdecisions more efficiently and accurately. Accordingly, the physical andrelative locations of the components, such as large functional blockslocated in a device layer or memory layer may be known by the networklayers for efficient routing and electrical communication routingdecisions. The layouts and relatively physical relationship of thecomponents blocks may be instantiated as a library exchange format (LEF)and/or design exchange format (DEF) as needed for fabrication.

In some instances, the network layers may have a master/slaverelationship. In this regard, one or more network layers may be masterlayers capable of making and providing routing decisions on behalf ofother network layers, referred to as slave network layers.

Utilization of the multiple network layers, such as network layers 704a-d, may reduce the impact of the large blockages created by components,by routing data around the blockages in an efficient manner. As aresult, a more flexible electric communication subsystem and wiringoptions may be obtained, providing adjustable or programmable electricalcommunication paths among the components with minimum impact from thepotential blockage created from the components in the device layers.

FIG. 8A depicts another example of a stacked SoC 800, similar to theinterconnection 700 depicted in FIG. 7, but with fillers 802, 804disposed in device layers 706 and 702 d. Fillers may be utilized when adie-to-wafer bonding technology is utilized. For example, when a die,rather than an entire wafer, substrate, or device layer, is selected toindividually bond to a specific component in a device layer, a totalarea of the die may be less than to an area of the device layer wherethe die is bonded to. Thus, vacant gaps, grooves or spaces may be filledamong the adjacent bonded dies with fillers, such as insulatingmaterials.

For example, and as shown in FIG. 8A, filler 802 separates dies 756 and766 in device layer 706 and filler 804 separates dies 725 and 762 indevice layer 702 d. In the embodiment depicted in FIG. 8, the fillers802, 804 may be disposed among the bonded dies (e.g., 756 and 776, and752 and 762) without blocking the ability of the network layers, such as704 c and 704 d.

In some examples, fillers may be extended into the network layersthereby creating separate networks on a single network layer. Forexample, and as shown in stacked SoC 801 in FIG. 8B, filler 806 extendsfrom device layer 702 d into network layer 704 c, thereby splittingnetwork layer 704 c into two parts. Similarly, filler 808 extends fromdevice layer 706 through network layer 704 d, thereby splitting networklayer 704 d into two discrete networks.

FIG. 9A shows the interconnection of components of a network layer 904with components of an ASIC layer. In this regard, routers 910-913 areconnected via routing traces 920 on the network layer 904. Although FIG.9A illustrates the components of the network being configured in a meshtopology, the network may be configured in any topology such as a ringtopology, start topology, etc.

The ASIC layer includes a plurality of processors, including processors940 and 942 that include network interfaces 941 and 943, respectively.The components of the ASIC layer are connected to the network layer viaconductive structures, including conductive structures 930 and 933 thatconnect network interfaces 941 and 943 to router 910 and 913,respectively. Although FIG. 9A illustrates the conductive structures assingle lines, the conductive structures may include any combination ofterminals, contacts, vias, conductive interconnects, etc. as describedherein. Moreover, although FIG. 9A shows only processors in the ASIClayer, other components such as GPUs, DSPs, etc. may be present in theASIC layer.

FIG. 9B shows a portion of an interconnection having more than onenetwork layer, including network layers 904 and network layer 906,connecting components from more than one ASIC layer. Similar to theconfiguration described in FIG. 9A, routers 910-913 from the firstnetwork layer 904 are connected via routing traces 920. Routers 955 and956 from the second network layer 906 are connected via routing traces957. Data may be sent from processor 940 in the first ASIC layer toprocessor 960 in a third ASIC layer via network layers 904 and 906, aswell as an intermediary ASIC layer as illustrated by the bolded lines.In this regard, data may be sent from processor 940 to network layer 904via network interface 940 and conductive structure 930. The data maytravel through routers 910-913 via routing traces 920. Router 913 maythen direct the data to processor 950 via conductive trace 951.Processor 950 may pass the data to network layer 906 via networkinterface 954. The data may then travel from router 955 to router 956,via routing traces 957. Router 956 may then pass the data to networkinterface 964 of processor 960 via conductive structure 961.

It is noted that the numbers of the components in the ASIC layers andthe network layers depicted in FIG. 10B is only for illustrationpurposes. Any numbers of the components in the ASIC layers and thenetwork layers may be utilized as needed.

FIG. 10A shows the interconnection of ASIC layer 1002 (similar to theASIC layer 102 depicted in FIG. 1) with memory layer 1006 (similar tothe memory layer 106 depicted in FIG. 1) through the network layer 1004(similar to the network layer 104 depicted in FIG. 1). In this regard,processors or other components on the ASIC layer, including processors1042 and 1044 are connected via conductive structures 1030 to thenetwork layer 1004. The network components on the network layer 1004 areconnected to memory segments, such as memory segments 1050-1054 in thememory layer 1006 via conductive structures 1032. For clarity,networking components, including routers and routing traces are notshown in the network layer 1004. It should be understood that eachcomponent in the ASIC layer 1002 connects to one or more routers in thenetwork layer 1104. For clarity, only a subset of the components on theASIC layer and memory segment on the memory layer are labeled in FIG.10A.

To read and write data to memory segments in the memory layer 1006, aprocessor such as processor 1042, or another component in the ASIC layer1002, may pass data and/or instructions to the network layer 1004 viaconductive structures 1030. The data may be packetized by networkinterfaces prior to being transmitted to the network layer. The routersmay direct the data and/or instructions to the appropriate memorysegments, such as memory segment 1050, on the memory layer 1006. Thedata may be depacketized after reaching memory segment 1050. Given theproximity of the memory layer 1006 to the components in the ASIC layer1002, the memory segments, such as memory segments 1050-1052 in thememory layer may effectively operate as L2 cache memory.

In some instances the routers may direct data and/or instructions tomemory located off of the SoC package. For example, and as furtherillustrated in FIG. 10A L3 memory 1080 may be connected to the networklayer 1004 via one or more conductive structures, such as conductivestructure 1034. In operation, a processor or other component of the ASIClayer 1002 may pass instructions and/or data to the network layer 1004.The data and/or instructions may be routed through the network layer viaone or more routers to conductive structure 1034. The data and/orinstructions are passed through the conductive structure 1034 to the L3memory 1080. The routers may direct data and/or instructions to otherdevices, such as other processors, located off the SoC package via oneor more conductive structures. Additional network layers may be furtherformed on the memory layer 1006 and similarly constructed to facilitatefurther vertical communications in the device layers formed in the SoC.In some instances, the network layer may be configured to disregardfaulty or otherwise nonfunctional memory segments as needed.

FIG. 10B illustrates an interconnection having two network layers 1004and 1005. In this regard, data from a first device layer (not shown) maybe transmitted to memory layer 1006. Network layer 1005, positionedbetween the first device layer and ASIC layer 1002, may receive the dataand forward it to ASIC layer 1002 via conductive structures 1015. Thedata may then be passed to network layer 1004 via conductive structures1030, which in turn may direct the data to memory layer 1006 viaconductive structures 1032.

In some instances, the network layer may be configured to disregardfaulty or otherwise nonfunctional memory segments. For example, and asillustrated in FIG. 11, memory segment 1150 on memory layer 1106 may befaulty. As a result, network layer 1104 may ignore memory segment 1150by not routing any data to that memory segment via conductive structure1133. Faulty memory segments may be determined by performing knownmemory testing during production of the SoC or memory, such that ane-fuse can set bad sectors. In some instances, faulty memory segmentsmay be detected during operation (down cycles) or during boot-up of theSoC. In this regard, a basic MBIST (Memory Built-in Self-Test) canevaluate the sectors in each memory segment to determine which segmentsor sectors in the segment are fully operational and which ones are not.Conversely the same approach may apply to a multi-processor approachwhere the network layer can ignore and route around faulty processors orprocessing elements arranged on the ASIC layer or other layer.

Although the layers described above are identified as having distinctcomponents and features, such as a memory layer having memory, a networklayer having networking components, and an ASIC layer includingcomputing components, each layer may include components associated withanother layer. For instance, memory layers may include networkingcomponents and/or computing components, network layers may includememory and/or computing components, and ASIC layers may includenetworking components and/or memory.

The invention claimed is:
 1. A system on chip (SoC) comprising: aplurality of network layers including a first network layer and a secondnetwork layer, each network layer including one or more routers; and afirst device layer including one or more components, the first devicelayer having an active surface and a second opposite surface, the activesurface being bonded to the second network layer and the second oppositesurface being bonded to the first network layer, wherein at least afirst component and a second component of the one or more componentseach include a network interface, wherein the network interface of thefirst component and the network interface of the second componentconnect the first and second components to the first network layer andthe second network layer via conductive structures, and wherein thefirst network layer and the second network layer are configured to routedata from the first component to the second component.
 2. The system ofclaim 1, wherein the first network layer and the second network layerare configured to route data to and from the one or more components onthe first device layer.
 3. The system of claim 1, wherein the firstnetwork layer is configured to control operation of the second networklayer.
 4. The system of claim 1, wherein the first network layer and thesecond network layer are configured to operate independently.
 5. Thesystem of claim 1, wherein the conductive structures comprise one ormore of traces, vias, contacts, or terminals.
 6. The system of claim 1,wherein the network interface of the first component and the networkinterface of the second component are configured to packetize anddepacketize data.
 7. The system of claim 1, wherein the first devicelayer comprises at least one of an application specific integratedcircuit (ASIC) layer or a memory layer.
 8. The system of claim 1,wherein the plurality of network layers each comprise an active surfacehaving one or more contacts; and a second surface opposite the activesurface having one or more contacts.
 9. The system of claim 8, whereinthe second surface of the second network layer is bonded to the activesurface of the first device layer and the active surface of the firstnetwork layer is bonded to the second surface of the first device layer.10. The system of claim 9, further including a memory layer including anactive surface having one or more contacts, the active surface of memorylayer being bonded to the active surface of the second network layer.11. The system of claim 10, wherein the memory layer includes one ormore memory segments, each of the one or more memory segments beingconnected to at least one of the one or more routers in the secondnetwork layer via one or more conductive structures.
 12. The system ofclaim 11, wherein the second network layer is configured to route databetween the one or more components in the first device layer and the oneor more memory segments.
 13. The system of claim 10, wherein the bondsbetween the first device layer and first and second network layers, andthe bonds between the memory layer and the second network layer areformed via ZiBond direct bonding and/or direct bond interconnect (DBI)hybrid bonding.
 14. The system of claim 9, further including a seconddevice layer including one or more components, the second device layerhaving an active surface and a second opposite surface, the secondopposite surface being bonded to the active surface of the secondnetwork layer.
 15. The system of claim 14, including a third devicelayer including one or more components, the third device layer having anactive surface and a second opposite surface, the active surface beingbonded to the second surface of the first network layer.
 16. The systemof claim 14, wherein the first and second network layers are configuredto route data between the one or more components on the third devicelayer and the one or more components in the second device layer.
 17. Thesystem of claim 16, wherein the bonds between the first device layer andfirst and second network layers, the bonds between the second devicelayer and the second network layer, and the bonds between the thirddevice layer and the first network layer are formed via ZiBond directbonding and/or direct bond interconnect (DBI) hybrid bonding.
 18. Thesystem of claim 14, wherein the first and second network layers areconfigured to ignore faulty memory segments or faulty processors. 19.The system of claim 1, wherein the one or more components include one ormore of processors, graphics processing units (GPUs), logic boards,digital sound processors (DSP), or network adaptors.
 20. The system ofclaim 1, wherein the one or more routers of the first and second networklayer are connected via one or more routing traces in each respectivenetwork layer.
 21. The system of claim 1, wherein the first and secondnetwork layers are connected to memory located outside of the SoC.